1. Technical Field
The present disclosure relates to a system and method for controlling exhaust gas recirculation (EGR) for an internal combustion engine using a pintle-type EGR valve.
2. Background Art
Exhaust gas recirculation (EGR) is a well-known engine control strategy that uses a controllable amount of exhaust gas during a subsequent combustion cycle to improve fuel economy and manage emissions. EGR may include internal EGR, or exhaust gas that remains in the cylinders after combustion, and external EGR, which is routed through a pipe or tube from the exhaust back to the intake. The amount of internal EGR can be varied by controlling the open/close timing of the intake and/or exhaust valves. Depending on the particular implementation of the intake and/or exhaust valve control, desired EGR flow may be difficult to obtain under some operating conditions, such as mid-to-high speeds and loads. External EGR is usually controlled by a flow control valve that may be electrically, pneumatically (using vacuum), and/or mechanically actuated. Solenoid-type, stepper motor and DC motor EGR valves are controlled by an electrical signal generated by the engine/vehicle controller and provide the greatest control flexibility, but are considerably more expensive and may require additional development and calibration time than mechanically or pneumatically actuated valves. Mechanically or pneumatically actuated valves that include a diaphragm typically have temperature constraints that require them to be positioned away from the exhaust manifold and connected using an additional pipe or tube.